Area of a triangle is always half of its respective rectangle

Instructions
1. Move any of the points A, B, and C to create a triangle[br]2. Click on the button "Animate"[br]3. Note: Can you see why the area of a triangle is ALWAYS half of the area of a rectangle?[br][br]
– wootwoot, Duane Habecker

Information: Area of a triangle is always half of its respective rectangle